If you think of European empire prior to the 19th century, where did they extend their control over other lands? It was mostly in the Western hemisphere. France and Spain and others had large colonial territories in the Americas. During the years following the French Revolution in Europe (which happened at the end of the 18th century), Napoleon came to power and the Napoleonic wars were fought across Europe. The focus of Napoleon's attention was on Europe, not on colonies across the ocean. So, for instance, he sold off the Louisiana Purchase to the United States. Elsewhere across the Americas, native populations took advantage of the changes in Europe to rebel against colonial governments. Napoleon had taken control over Spain and other parts of Europe as well as France, and a wave of independence movements broke out in colonial territories in Central America and South America.
When Europe resumed efforts to extend its control over other parts of the world, later in the 19th century (and into the early 20th century), they shifted their focus to Africa and Asia. There was a race for controlling territories across all of Africa and especially in southeast Asia. In Africa, only Ethiopia and Liberia managed to maintain their independence from European control when that wave of imperialist action took place.
"(2) Mali would have flourished without Mansa Musa’s influence" is an opinion rather than a fact since there is no way of proving that this would have happened.
The time period after the war of 1812 which saw only one political party was called the Era of Good Feelings.
Neither one of the sides were fruitful in getting through the resistance of the other and bringing about a stalemate. Trench fighting developed due the disappointment of the Schliffen Plan. It was another arrangement of fighting which was an immediate reason for the stalemate, and this is the reason. It was an arrangement of resistance not offense.
